Journal of Thermal Engineering最新文献_第6页

Experimental assessment of tio2-poe nanolubricant stability and optimization process using one factor at a time (OFAT) based on response surface methodology 基于响应面法的一因素一次法（OFAT）对tio2-poe纳米润滑剂稳定性和优化过程的实验评估

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-04-18 DOI: 10.18186/thermal.1285208

Agus Nugroho, R. Mamat, Zhang BO1, Wan HAMZAH AZMI, T. Yusaf, F. Khoerunnisa

引用次数: 0

Simulation and redesigning the methanol production cycle using coil-wound liquefied natural gas heat exchangers 盘绕式液化天然气换热器甲醇生产周期的模拟与再设计

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-04-18 DOI: 10.18186/thermal.1285190

S. Farahbakhsh, Mohammad Mehdi KESHTKAR1

引用次数: 0

Impact of the V CAP on induced turbulent air flow in a solar chimney: a computational study V CAP对太阳能烟囱内诱导湍流气流影响的计算研究

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-04-18 DOI: 10.18186/thermal.1285240

N. Phu, Nguyen Hoang Kha, N. Hap

{"title":"Impact of the V CAP on induced turbulent air flow in a solar chimney: a computational study","authors":"N. Phu, Nguyen Hoang Kha, N. Hap","doi":"10.18186/thermal.1285240","DOIUrl":"https://doi.org/10.18186/thermal.1285240","url":null,"abstract":"In this paper, a 2D numerical simulation of a solar chimney with a top V cap was performed to evaluate the induced air flow degradation. Dimensions including the width of the cap and the cap offset from the top of chimney are specified as key parameters. Meanwhile, height and width of the chimney are fixed. The numerical model was confirmed to be accurate compared to the published data. The results showed that reducing the offset and increasing the width reduces airflow through the chimney. The effect of offset on chimney intake air is significant. When considering the addition of the top V cap, the airflow is reduced by about 20% compared to the chimney without a cap. This is because the cap forms three primary vortices including one vortex below the cap and two ones above the cap. The vortex under the cap in the direction from the absorber plate to the glass cover increases the air flow out of chimney at the side of the glass cover. The region with great turbulent kinetic energy forms at upper side of the cap. The air flow correlation as a function of the heat flux to the absorber plate, cap offset and cap width have been developed with errors of less than 2.5%.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47453117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical assessment of stability behaviour in supercritical CO2 based NCLS configured with heater, heat exchanger and isothermal wall as heat source 以加热器、换热器和等温壁为热源的超临界CO2基NCLS稳定性的数值评估

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-04-18 DOI: 10.18186/thermal.1285268

Srivatsa Thimmaiah, Tabish Wahidi, A. Yadav, A. Mahalingam

{"title":"Numerical assessment of stability behaviour in supercritical CO2 based NCLS configured with heater, heat exchanger and isothermal wall as heat source","authors":"Srivatsa Thimmaiah, Tabish Wahidi, A. Yadav, A. Mahalingam","doi":"10.18186/thermal.1285268","DOIUrl":"https://doi.org/10.18186/thermal.1285268","url":null,"abstract":"Three-dimensional numerical analysis is presented in this study to assess the transient and stability behaviour of supercritical CO2 (sCO2) based NCLs configured with three different types of heat sources, i.e., heater, a hot heat exchanger (HHX) and isothermal wall (ISO) at the source, and a cold heat exchanger (CHX) at the sink in all three NCLs. Unsteady threedimensional conservation equations (mass, momentum and energy equations) are solved to assess the transient and stability behaviour of sCO2 mass flow rate, temperature and velocity as a function of time. Further, the effect of pressure on sCO2 mass flow rate is also assessed to compare the loops performance. Performance of the loop has been studied for various heat inputs at the source by keeping constant mass flow rate and temperature at the sink. It is observed that for any boundary condition at the source, the loop experiences some initial disturbances or instabilities before reaching the steady-state. However, the time needed to attain a steady-state varies with the nature of heat input employed at the source. Results show a higher magnitude of instabilities in the Heater-CHX loop than HHX-CHX and ISO-CHX loops, and these instabilities mitigate at a faster rate in the ISO- CHX loop at all levels of heat input and operating pressure of the loop. It is also observed that as loop fluid operating pressure increases, the instability of the system decreases and the loop fluid mass flow rate increases. Further, the Nusselt number in the Heater-CHX loop is more than other loops because of its high turbulent kinetic energy. The findings of this study are validated with the published experimental and numerical data and found a good agreement.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48200106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The optimal geometric design of a v-corrugated absorber solar air heater integrated with twisted tape insert v型波纹吸收式扭带式太阳能空气加热器的优化几何设计

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-04-18 DOI: 10.18186/thermal.1285214

Issam M. Ali Aljubury, Mohammed Khalil Hussain, Ammar A. Farhan

{"title":"The optimal geometric design of a v-corrugated absorber solar air heater integrated with twisted tape insert","authors":"Issam M. Ali Aljubury, Mohammed Khalil Hussain, Ammar A. Farhan","doi":"10.18186/thermal.1285214","DOIUrl":"https://doi.org/10.18186/thermal.1285214","url":null,"abstract":"The proper design of a solar air heater depends on the highest thermal performance of the solar collector. In the present paper, proposed a method to find an optimal dimension of V-corrugated absorber solar air heater (VSAH) combined with a twisted tape insert (TTI). The design variables of the VSAH-TTI are length, width, number of channels, and twisted tape ratio. The effect of each design variable is examined and studied under various ranges of Reynolds number (Re). Given the complexity in changing design variables of solar collector having a V-corrugated absorbing plate with twisted tape insert (VSAH -TTI) to find the highest thermal performances, the multi-objective function genetic algorithm is used to find the optimal dimensions of VSAH-TTI based on maximizing the heat gain, thermal and effective efficiency as well as minimizing the pressure drop on solar collector. The range of each design variable of the VSAH-TTI by means of length (1 – 2.5 m), width (0.5 – 1.5 m), number of channels (4 – 14), and twisted tape ratio (1 – 8) are specified in paper based on the most common practical values of the solar collector. The results showed for the case under study that each design variable of VSAH-TTI affect the thermal performance and the optimized geometry by using a genetic algorithm (Ga) can find the optimal geometric dimensions of VSAH-TTI. The optimal dimension by using Ga can increase the heat gain by more than 8% and increase the effective and thermal efficiency of more than 7% for the original geometry. Furthermore, the optimized geometry can reduce more than 29% for the original geometry. These improvements in optimized geometry for VSAH- TTI without introducing any additional items.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47676446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Experimental and numerical analysis of the forced draft wet cooling tower 强制通风湿式冷却塔的实验与数值分析

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-04-18 DOI: 10.18186/thermal.1285257

N. Lafta, F. Kareem, M. Ghafur

{"title":"Experimental and numerical analysis of the forced draft wet cooling tower","authors":"N. Lafta, F. Kareem, M. Ghafur","doi":"10.18186/thermal.1285257","DOIUrl":"https://doi.org/10.18186/thermal.1285257","url":null,"abstract":"Cooling towers are essentially large boxes designed to maximize the evaporation of water. The inlet water temperature and water to air mass flow rate ratio (L/G) significantly affect the performance of the cooling tower. The number of a transfer unit (NTU), Merkel number (Me), Lewis number (Le), and efficiency of the cooling tower define the performance of the forced cooling tower. In this research paper, different inlet water temperatures ranging from 28 °C to 42 °C and (L/G) ranging from 0.5, 1, and 1.5 were used to investigate the performance of the forced cooling tower. Mathematical modeling equations were used to calculate NTU, Me, Le, and efficiency at different inlet water temperatures and (L/G). Engineering equation solver (EES) software was used to solve these mathematical modeling equations. Further, an experimental investigation was carried to find forced cooling tower performance at different inlet water temperatures and (L/G), and results were compared with the theoretical results. The results revealed that increasing the inlet water temperature, NTU, Me, Le, and efficiency increased and were directly related to each other. Further, NTU and efficiency were increased by increasing (L/G). At the same time, the Me and Le reduced with (L/G). Finally, an acceptable and better agreement has been obtained between experimental and theoretical results. Based on obtained results, it has been concluded that higher values of inlet water temperature and (L/G) provided the higher performance of the forced cooling tower.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48060847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A theoretical analysis on the operating and design parameters affecting the performance of a sewage wastewater sourced heat pump system 对影响污水源热泵系统性能的运行参数和设计参数进行了理论分析

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-04-18 DOI: 10.18186/thermal.1285281

Ercan Dogan, İsmail Solmaz, Ö. Bayer

{"title":"A theoretical analysis on the operating and design parameters affecting the performance of a sewage wastewater sourced heat pump system","authors":"Ercan Dogan, İsmail Solmaz, Ö. Bayer","doi":"10.18186/thermal.1285281","DOIUrl":"https://doi.org/10.18186/thermal.1285281","url":null,"abstract":"Sewage wastewater heat exchanger (SWHE) has a significant role in the performance of sewage wastewater sourced heat pump (SWSHP) system as it provides to transfer the energy of wastewater to intermediary fluid or working fluid. Thus, a theoretical analysis of the SWSHP system was carried out to investigate the effects of SWHE design parameters on the system ’s performance. For this purpose, a simulation program based on the proposed mathematical model of the SWSHP system was developed in MATLAB. Afterward, the indirect type SWSHP system that can meet 50 kW heating load was theoretically designed. The influences of SW temperature, its mass flow rate, the inner diameter of the heat exchanger tube, and intermediary fluid mass flow rate on the performance of the designed SWSHP system were analyzed. The results indicate that variation of SW temperature affects the COPsys more than the variation of SW mass flow rate. Considering the ranges of parameters investigated, the COPsys raises from 2.56 to 4.51 and 2.89 to 4.27 with the variations of SW temperature and SW flow rate, respectively. Moreover, an increase in the intermediary fluid mass flow rate provides an improvement on the COPsys and COPunit. However, SWSHP performance is adversely affected by the increasing value of the inner diameter of the tubes. As a result, small changes in the design parameters of the SWHE directly affect the system performance and system operating conditions.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67514809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Prediction of recital characteristics of a CI diesel engine operated by bio-fuel extracts from cotton seed oil, linseed oil and mahua seed oil using ANN metho 应用人工神经网络方法预测棉籽油、亚麻籽油和马化油生物燃料提取物对CI柴油机性能的影响

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-04-17 DOI: 10.18186/thermal.1284626

Srinivasa REDDY KUNDURU, Hanumantha Rao YARRAPATHRUNI VENKATA, D. Vallapudi, Narmatha Deenadayalan, A. Kumaravel

{"title":"Prediction of recital characteristics of a CI diesel engine operated by bio-fuel extracts from cotton seed oil, linseed oil and mahua seed oil using ANN metho","authors":"Srinivasa REDDY KUNDURU, Hanumantha Rao YARRAPATHRUNI VENKATA, D. Vallapudi, Narmatha Deenadayalan, A. Kumaravel","doi":"10.18186/thermal.1284626","DOIUrl":"https://doi.org/10.18186/thermal.1284626","url":null,"abstract":"In the wide survey, it is explored that the potential of artificial neural network is used to foretell the recital (performance) characteristics of a four stroke single cylinder diesel engine using the biofuel obtained from cottonseed, linseed and Mahua seed. The test engine was powered with diesel and biofuel with its blends from cotton seed, linseed and Mahua seed separately. Experimental results of the cotton seed oil, linseed oil and mahua oil as a substitute for diesel revealed that linseed oil provides the better engine performance nearly equal to diesel. The ANN is used to compute the performance characteristics such as Indicated power, Brake power, Friction power, Thermal efficiency, brake mean effective pressure, brake thermal efficiency, Brake specific fuel consumption, Indicated thermal efficiency, indicated mean effective pressure, Mechanical efficiency, Indicated specific fuel consumption, volumetric efficiency and combustion characteristics as compression ratio at different conditions of torque, speed, water flow , air rate and fuel rate. An ANN sculpt was developed with 80% of training data and 20% of testing data from experimental values. In this model, back propagation feed forward neural network with five inputs and eleven outputs has been used. The ANN model result accuracy was found to agree nearly with the experimental results with the regression coefficient value approximately equal to one and low mean square error value. Thus, the proposed ANN model was legitimate tool for predicting the combustion and performance of diesel engine.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45298350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Combined effect of upstream ramp and effusion cooling in combustion chamber liners of gas turbin 燃气轮机燃烧室内胆上游斜坡与射流冷却的联合效应

Journal of Thermal Engineering Pub Date : 2023-04-17 DOI: 10.18186/thermal.1284759

Yellu KUMAR, Adnan QAYOUM, Shahid SALEEM, Fasil QAYOUM MIR

{"title":"Combined effect of upstream ramp and effusion cooling in combustion chamber liners of gas turbin","authors":"Yellu KUMAR, Adnan QAYOUM, Shahid SALEEM, Fasil QAYOUM MIR","doi":"10.18186/thermal.1284759","DOIUrl":"https://doi.org/10.18186/thermal.1284759","url":null,"abstract":"Effusion cooling technique is a highly efficient cooling method used to reduce the thermal stresses of combustion chamber liners in a gas turbine engine. The present study focuses on enhancing the adiabatic effectiveness of effusion cooling. The computational investigations are carried out using COMSOL Multiphysics 5.4 with the standard k- ε turbulence model. Detailed computations for 20 rows of effusion holes on the flat plate are examined for blowing ratios 0.25, 0.5, 1.0, 3.2, and 5.0 for each set of injection angles 30o and 60o. To enhance the effusion cooling performance, an upstream ramp (ramp angles 14o, 24o, and 34o) is introduced before the upstream of effusion holes. The results show that the adiabatic effectiveness increases with an increase of blowing ratio and ramp angles. By placing an upstream ramp, the low blowing ratios can greatly increase the adiabatic effectiveness by 29%, 31%, and 35% for ramp angles of 14o, 24o, and 34o, respectively. For high blowing ratios, an increase in the angles of the ramp shows less impact on adiabatic effectiveness throughout the effusion surface. However, adiabatic effectiveness has increased by 26% compared to the baseline model. It is also observed that injection angle of 30o provides more effectiveness than 60o. This study concludes that placing an upstream ramp increases the effusion cooling performance in the combustion chamber liners of a gas turbine engine","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136022202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical investigation on the effect of slit thickness and outlet angle of the bladeless fan for flow optimization using CFD techniques 基于CFD技术的无叶风扇狭缝厚度和出口角对流动优化影响的数值研究

Journal of Thermal Engineering Pub Date : 2023-04-17 DOI: 10.18186/thermal.1284657

Dineshkumar RAVI, Thundil Karuppa RAJ RAJAGOPAL

{"title":"Numerical investigation on the effect of slit thickness and outlet angle of the bladeless fan for flow optimization using CFD techniques","authors":"Dineshkumar RAVI, Thundil Karuppa RAJ RAJAGOPAL","doi":"10.18186/thermal.1284657","DOIUrl":"https://doi.org/10.18186/thermal.1284657","url":null,"abstract":"The effect of outlet thickness and outlet angle of the bladeless fan have been an alysed numerically on the aerodynamic performance of the bladeless fan. Five different aerofoil profiles have been considered for the present work is Eppler 479, Eppler169, Eppler 473, S1046 and S1048. The bladeless fan arrangement has been achieved by converting the aerodynamic models listed above. The ANSYS ICEM CFD 16.0 have been used to discretize the enclosure and bladeless fan through finite volume approach. The mesh model is then imported into ANSYS CFX 16.0 pre-processor for applying the required boundary conditions. The governing equations namely continuity and momentum are used to solve the flow physics through and across the bladeless fan and SST k-? turbulence model has been used to predict the turbulence in the bladeless fan. The effect of outlet thicknesses and outlet angles have been varied for all the five aerofoil configurations mentioned and the volumetric flow at inlet have been adjusted from 5 LPS to 80 LPS. Outlet thickness is varied from 0.8, 1.0, 1.3, 1.5 and 2 mm and the slit angle is varied from 20 degrees to 80 degrees in step of 10 degrees. The results predicted that Eppler 473 aerofoil profile showed better performance when the thickness of slit and outlet angle has been fixed constant as 1 mm and 70 degree respectively. Also, the maximum discharge flow ratio is recorded for an inlet volumetric flow rate of 80 LPS and it is found to be 34.37. The present numerical study substantiated that outlet thickness plays a dominant role on the bladeless fan’s aerodynamic performance compared to outlet angle and aerodynamic shape considered in this numerical analysis. The contours of velocity, streamline and pressure of the bladeless fan have been discussed.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136081465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0